I already explained this in the other thread that, the outfits they are wearing are for the 1973 setting, but the backdrop is not since they could be only doing test shots. Or the time travel takes place in the subbasement. 1 moment they are in the subbasement and the next, they are in 1973.

I don't think it makes sense for the time travel to be in the subbasement, or at least with that picture because that is definitely a 1973 Hank McCoy. It could be a test shot, but I think the subbasement is the 1973 set. If Xavier built Cerebro in the mansion, which seems like a possibility, why wouldn't he update the subbasement too?

__________________"The public will believe anything, so long as it is not founded on truth." - Edith Sitwell